Energy Regenerative Actuator for Motion Control With Application to Fluid Power Systems

Abstract

Motion control is principally involved with moving a load along some prescribed trajectory. Flight simulators and numerically controlled machine tools are examples where motion control is required. Actuators for motion control are typically electrohydraulic, electropneumatic, or electromechanical. An electric signal from a controller modulates high-power elements that control motion of a load in some prescribed manner. Since loads are continuously being accelerated and decelerated, actuators absorb energy as frequently as they output energy, but power is required from the supply regardless of the direction of power flow in the actuator. The absorbed power is simply dissipated in the actuator or power supply. An actuator concept is developed here in which energy storage elements become part of the actuator, and absorbed power is recovered while still performing a high level of motion control. The concept is developed for a fluid power application, but is not restricted to fluid-type devices. Practical realizations of this concept will allow downsizing of power supplies as well as reduced power consumption for any particular application.